Quartz crystal microbalance use in biological studies

Design, development, and applications of quartz crystal microbalance are discussed. Two types of crystals are used. One serves as reference and other senses changes in mass. Specific application to study of bacterial spores is described

Femtosecond dynamics of solvated oxygen anions. II. Nature of dissociation and caging in finite-sized clusters

Ultrafast dissociation and recombination dynamics of (O_2)^−_n, n=3–10 was studied using femtosecond,time-resolvedphotoelectron spectroscopy. The observed transients of nascent fragment anions, following 800 nm fs pulse excitation, exhibit a biexponential rise with two distinct time constants. The time constants, which vary with the number of solvent O_2 molecules, clearly show the solvation effect in two different dissociation pathways. Consistent with the bifurcation picture in the preceding paper, the direct subpicosecond dissociation(τ_1=110-620 fs, depending on n) is governed by electron recombination and kinematics of the half-collision. The second pathway is indirect (τ_2=0.7–8.0 ps, for O^−_6 to O^−_(20)) and controlled by intramolecular vibrational-energy redistribution. In the solvent cage, only O^−_(16), O^−_(18), and O^−_(20) show the reformation of the bond, with the caging time constant decreasing from 4 ps for the first two to 2 ps for the latter. This caging through ion-induced dipole interaction is then followed by vibrational relaxation on the time scale of 12 to 3 ps, for O^−_(16) to O^−_(20). The time scale for the initial direct caging is two to five times slower than that previously observed for diatoms, neutral, or ionic, in van der Waals clusters. We suggest that this initial slower caging is due to the reorientation of O^−_2 and O_2 to acquire a proper geometry for O^−_4 bond reformation. In these finite-sized homogeneous clusters, we compare theory with experiment. We also found a correlation between the vertical detachment energy and n^(−1/3), for n in the range of 2–10, which allow for a connection between the mesoscopic structures and a bulk-type dielectric continuum, with an effective dielectric constant

Poor survival outcomes in HER2 positive breast cancer patients with low grade, node negative tumours

We present a retrospective analysis on a cohort of low-grade, node-negative patients showing that human epidermal growth factor receptor 2 (HER2) status significantly affects the survival in this otherwise very good prognostic group. Our results provide support for the use of adjuvant trastuzumab in patients who are typically classified as having very good prognosis, not routinely offered standard chemotherapy, and who as such do not fit current UK prescribing guidelines for trastuzumab

Femtosecond dynamics of solvated oxygen anions. I. Bifurcated electron transfer dynamics probed by photoelectron spectroscopy

The ultrafast dissociationdynamics of O−_6⋅X (X=O_2, N_2, Xe, or N_2O) was investigated by femtosecondphotoelectron spectroscopy. The transients, monitoring nascent O−_2, exhibit biexponential rises with two distinct time constants—the fast component (τ_1∼200 fs) corresponds to the joint rate constant for electron recombination and direct dissociation of the O−_4 core perturbed by solvent molecules, whereas the slow component (τ_2=2.0–7.7 ps, depending on the solvent) corresponds to the process for the liberation of O−_2, which is governed by vibrational predissociation and intramolecular vibrational-energy redistribution. These observations are consistent with the mechanism proposed in the earlier communication of this work [Paik et al., J. Chem. Phys. 115, 612 (2001)]. The wave packet bifurcates via two separate dissociation pathways: electron transfer followed by electron recombination, and electron transfer followed by vibrational predissociation. Unlike all other solvents, the anomalous behavior observed for O−_6⋅N_2O—a threefold increase in τ_2 value, compared to the other solvents, and a factor of 10 increase for τ_2, compared to that of O−_6—reflects the more effective energy dissipation via solute–solvent vibration-to-vibration and rotational couplings. Moreover, for all solvents, the ratio of the slow-rise contribution to the total signal can be correlated with the degree of cooling, supporting the concept of bifurcation in the two channels

Cognitive Impairment among Older Adults in the Emergency Department

Background: Within the next 30 years, the number of visits older adults will make to emergency departments (EDs) is expected to double from 16 million, or 14% of all visits, to 34 million and comprise nearly a quarter of all visits.Objective: The objectives of this study were to determine prevalence rates of cognitive impairment among older adults in the ED and to identify associations, if any, between environmental factors unique to the ED and rates of cognitive impairment.Methods: A cross-sectional observational study of adults 65 and older admitted to the ED of a large, urban, tertiary academic health center was conducted between September 2007 and May 2008. Patients were screened for cognitive impairment in orientation, recall and executive function using the Six-Item Screen (SIS) and the CLOX1, clock drawing task. Cognitive impairment among this ED population was assessed and both patient demographics and ED characteristics (crowding, triage time, location of assessment, triage class) were compared through adjusted generalized linear models.Results: Forty-two percent (350/829) of elderly patients presented with deficits in orientation and recall as assessed by the SIS. An additional 36% of elderly patients with no impairment in orientation or recall had deficits in executive function as assessed by the CLOX1. In full model adjusted analyses patients were more likely to screen deficits in orientation and recall (SIS) if they were 85 years or older (Relative Risk [RR]=1.63, 95% Confidence Interval [95% CI]=1.3-2.07), black (RR=1.85, 95% CI=1.5-2.4) and male (RR=1.42, 95% CI=1.2-1.7). Only age was significantly associated with executive functioning deficits in the ED screened using the clock drawing task (CLOX1) (75-84 years: RR=1.35, 95% CI= 1.2-1.6; 85+ years: RR=1.69, 95% CI= 1.5-2.0).Conclusion: These findings have several implications for patients seen in the ED. The SIS coupled with a clock drawing task (CLOX1) provide a rapid and simple method for assessing and documenting cognition when lengthier assessment tools are not feasible and add to the literature on the use of these tools in the ED. Further research on provider use of these tools and potential implication for quality improvement is needed. [West J Emerg Med. 2011; 12(1):56-62.

Detectability of gravitational wave events by spherical resonant-mass antennas

We have calculated signal-to-noise ratios for eight spherical resonant-mass antennas interacting with gravitational radiation from inspiralling and coalescing binary neutron stars and from the dynamical and secular bar-mode instability of a rapidly rotating star. We find that by using technology that could be available in the next several years, spherical antennas can detect neutron star inspiral and coalescence at a distance of 15 Mpc and the dynamical bar-mode instability at a distance of 2 Mpc.Comment: 39 pages, 4 EPS Figures, some additional SNRs for secular instabilities, some changes to LIGO SNRs, Appendix added on the asymptotic expansion of energy sensitivity, corrected supernova rates. Results available at http://www.physics.umd.edu/rgroups/gen_rel_exp/snr.html Submitted to Phys. Rev.